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Testing Knapsack Sprayers

Written by Dr Friedrich of FAO and Dr Andreas Herbst from Julius Kühn Institute (JKI, formerly BBA) Braunschweig, Germany

Why test knapsack sprayers?

Poor knapsack sprayer design can lead to 

  • the operator being unnecessarily exposed to pesticides,
  • environmental contamination, 
  • residues of pesticides on produce.

Testing knapsack sprayers will be a first step to ensuring compliance with the requirements of the International Standard ISO 19932 2006 promoting safer use. 

What's the problem?

Side lever knapsack sprayers are used and sold in millions every year and their safe use is essential...

Image of knapsack spraying stall and stall keepers (18 Kb JPEG)

... but knapsack spraying presents more risk of operator exposure than other methods.

Image of person knapsack spraying without adequate personal protective equipment (11 Kb JPEG)

Crop protection products (pesticides) are applied in many ways; using for example, tractors, airplanes and - as with knapsacks - human energy.

Image showing horticultural sprayer, aerial spraying and knapsack spraying (14 Kb JPEG)

Unlike other spraying methods, the operator carries the knapsack sprayer with the spray solution in a tank very close to his body ......

Image of person spraying with a knapsack sprayer (22 Kb JPEG)

... with his hand operating and directing a spraying nozzle just a few centimetres away.

If a knapsack sprayer leaks from its lid opening then this could contaminate the operator's body...

Image of knapsack sprayer leaking from lid and image of person spraying in a greenhouse (27 Kb JPEG)

.... whilst leaks from the trigger valve will contaminate his hands.

Leaks are just one way operators can be exposed to pesticides. Other risks also exist, for example, retained spray on the outside of sprayers caused by over filling and sprayers that too easily fall over on slightly uneven ground are two more.

Woman spraying cocoa - not wearing appropriate personal protective equipment (30 Kb JPEG)

Apart from concerns of operator safety, the poor application of pesticides may also cause serious environmental impacts. Knapsack sprayers must be suitable for their intended purpose and must be capable of applying pesticides such that the benefits of using pesticides are gained without environmental, consumer or other risks.

Compliance with the requirements of the International Standard will minimise operator exposure risks linked to poor knapsack sprayer design as well as unnecessary environmental contamination and residues of pesticides on produce. Testing will be a first step to ensuring compliance.